Father has hesitation getting small felines (5)
I believe the answer is:
pumas
'felines' is the definition.
(puma is a kind of feline)
'father has hesitation getting small' is the wordplay.
'father' becomes 'pa' (pa can mean dad or father).
'has' is an insertion indicator.
'hesitation' becomes 'um' (sound made when hesitating).
'getting' says to put letters next to each other.
'small' becomes 's' (abbreviation - e.g. clothes size).
'pa' enclosing 'um' is 'puma'.
'puma'+'s'='PUMAS'
(Other definitions for pumas that I've seen before include "Big felines" , "American wild cats" , "North American mountain lions" , "Big cats" , "Large American felines" .)